White balance

White balance adjusts color temperature of image to light source.
Generally, the fact that color temperature of image is not as same as subject's at
shooting time is not notable except when image and subject colors are compared
directly side by side. In my humble opinion, good human eye can compare only image taken from
the printed picture with original, on example from good calendar picture. The
auto color balance in most of digital cameras is generally not enough. The best
way to correct white balance is to adjust it as custom adjustment, or
better, calibrate it manually by using a white surface
(paper) in the place where picture will be taken.

Each type of light has a
numerical colour temperature:

Don't forget: even if you set the white balance at the shooting time, the
colors in light areas will be different as those in dark sides.

Twilight

4000K

Shade

6500K

Sunlight

6000K

Fluorescent

5500K - 4000K

Incandescent

3500K - 3000K

On left side the buttons of images with different white balance are showed. This is
not a good way to present the effect of WB settings, because the subject was
illuminated with sun light only.